抄録
In-plane tension and compression experiments on a copper alloy sheet (phosphor bronze) 0.25 mm in thickness for electronic parts were carried out using a specially designed testing apparatus. The testing apparatus was equipped with comb-shaped dies so that we could observe the stress-strain curves of sheet metal subjected to tension followed by compression, and vice versa, without causing the buckling of the specimen, as well as those for the monotonic tension and compression of the as-received material. A difference in the flow stresses of tension and compression was observed for the as-received alloy sheet. The Bauschinger effect was measured and the measured stress-strain curves were precisely approximated using Voce′s function. As a second part of the experiment, bending moment-curvature diagrams were observed for the as-received and prestrained specimens and compared with those calculated using the tensile and compressive stress-strain curves observed for them. The observed moment-curvature diagrams were in good agreement with the calculated ones when the strength differential effect was accurately modeled for the as-received specimens and when the Bauschinger effect was accurately modeled for the prestrained ones. Thus, we conclude that the accurate modeling of the strength differential and Bauschinger effects of the copper alloy is crucial for predicting the alloy′s bending behavior accurately.
